#!/usr/bin/env python

import sys, os, time, atexit, signal
from signal import SIGTERM

from bot import bot
import config, logging

# Daemon functionality for crappy-irc-bot
# Code borrowed from http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/

class Daemon:
    """
    A generic daemon class.
    Usage: subclass the Daemon class and override the run() method
    """
    def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
        self.stdin = stdin
        self.stdout = stdout
        self.stderr = stderr
        self.pidfile = pidfile

        self.logger = logging.getLogger('cib')
        
    def daemonize(self):
        """
        do the UNIX double-fork magic, see Stevens' "Advanced 
        Programming in the UNIX Environment" for details (ISBN 0201563177)
        http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
        """
        try: 
            pid = os.fork() 
            if pid > 0:
                # exit first parent
                sys.exit(0) 
        except OSError, e: 
            #sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
            self.logger.error("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1)

        # decouple from parent environment
        #os.chdir("/") 
        os.setsid() 
        os.umask(0)

        # do second fork
        try: 
            pid = os.fork() 
            if pid > 0:
                # exit from second parent
                sys.exit(0) 
        except OSError, e: 
            #sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
            self.logger.error("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1) 

        # redirect standard file descriptors
        sys.stdout.flush()
        sys.stderr.flush()
        si = open(self.stdin, 'r')
        so = open(self.stdout, 'a+', 0)
        se = open(self.stderr, 'a+', 0)
        os.dup2(si.fileno(), sys.stdin.fileno())
        #os.dup2(so.fileno(), sys.stdout.fileno())
        os.dup2(se.fileno(), sys.stderr.fileno())
        sys.stdout = so
        # write pidfile
        atexit.register(self.delpid)
        pid = str(os.getpid())
        open(self.pidfile,'w+').write("%s\n" % pid)
        
    def delpid(self):
        os.remove(self.pidfile)

    def start(self):
        """
        Start the daemon
        """
        # Check for a pidfile to see if the daemon already runs
        try:
            pf = open(self.pidfile,'r')
            pid = int(pf.read().strip())
            pf.close()
        except IOError:
            pid = None
        
        if pid:
            message = "pidfile %s already exists. CIB already running?\n"
            #sys.stderr.write(message % self.pidfile)
            self.logger.error(message % self.pidfile)
            sys.exit(1)

        # Start the daemon
        self.daemonize()
        self.run()

    def stop(self):
        """
        Stop the daemon
        """
        # Get the pid from the pidfile
        try:
            pf = file(self.pidfile,'r')
            pid = int(pf.read().strip())
            pf.close()
        except IOError:
            pid = None

        if not pid:
            message = "pidfile %s does not exist. CIB not running?\n"
            #sys.stderr.write(message % self.pidfile)
            self.logger.error(message % self.pidfile)
            return # not an error in a restart

        # Try killing the daemon process
        try: 
            os.kill(pid, 0)
        except:
            #sys.stderr.write("Bad PID? Deleting.\n")
            self.logger.error("Bad PID? Deleting.\n")

            if os.path.exists(self.pidfile):
                os.remove(self.pidfile)
            sys.exit(1)
        try:
            while 1:
                os.kill(pid, SIGTERM)
                time.sleep(0.1)
        except OSError, err:
            if err.errno == 3:
                if os.path.exists(self.pidfile):
                    os.remove(self.pidfile)
            else:
                #print str(err)
                self.logger.error(err)
                sys.exit(1)

    def restart(self):
        """
        Restart the daemon
        """
        self.stop()
        self.start()

    def run(self):
        """
        You should override this method when you subclass Daemon. It will be called after the process has been
        daemonized by start() or restart().
        """

class CIBDaemon(Daemon):
    def set_stop(self, *args):
        self.logger.info("!!! Recieved SIGTERM")
        if not self.bot._stop.is_set():
            self.logger.info("!!! Setting _stop")
            self.bot._stop.set()

    def run(self):
        self.logger.info("!!! CIB Starting")
        reconnect = True
        reconnect_delay = 15

        try: reconnect_delay = config.reconnect_delay
        except: pass
        
        signal.signal(SIGTERM, self.set_stop)

        while reconnect:
            b = bot()
            self.bot = b
            b.start()
            while b.isAlive():
                b.join(1)       # Without a timeout the process will deadlock
                                # and never execute the signal handler
            b.cmd.dispatch(None, ("", "DISCONNECT"))
            self.logger.info("!!! Unloading Plugins: %s" % self.bot.loaded_plugins)
            for p in list(b.loaded_plugins):
                b._unload_plugin(p)
            if b.shutting_down or b._stop.is_set():
                break
            self.logger.info("!!! Bot died - pausing (%d) for reconnect" % \
                    reconnect_delay)

            time.sleep(reconnect_delay)
            self.logger.info("!!! Attempting reconnect")

        self.logger.info("!!! Bot Exiting")
        sys.exit(0)
        
if __name__ == '__main__':
    main_log = "log/main.log"
    error_log = "log/error.log"
    pid_file = "cib.pid"
    version = "crappy-irc-bot"

    log = logging.getLogger('cib')

    try: main_log = config.log_main
    except: pass

    try: error_log = config.log_error
    except: pass

    try: pid_file = config.pid_file
    except: pass
    
    try: version = config.version
    except: pass
    
    cib = CIBDaemon(pid_file, stdout = main_log, stderr = error_log)

    if len(sys.argv) >= 2:
        if sys.argv[1] == 'fg' or sys.argv[1] == 'nofork':
            cib.run()
        else:
            if sys.argv[1] == 'stop':
                cib.stop()
            elif sys.argv[1] == 'restart':
                cib.restart()
            else:
                log.info(version,"Starting")
                cib.start()
    else:
        log.info(version,"Starting")
        cib.start()
